St. Louis-based Ascension Health, the largest nonprofit health system in the nation and the largest Catholic health system in the world, has finalized its acquisition of Presence Health, a Catholic health system in Chicago.

Here are four things to know about the transaction.

1. Ascension and Presence signed a letter of intent in August 2017 and entered into a definitive agreement in early February. Ascension announced the completed acquisition March 2.

2. Ascension now owns Presence, and most of Presence's facilities are part of Amita Health, a joint venture of Ascension's Alexian Brothers Health System in Arlington Heights, Ill., and Hinsdale, Ill.-based Adventist Midwest Health, which is part of Altamonte Springs, Fla.-based Adventist Health.

3. Presence's skilled nursing, assisted living and independent living facilities are now part of Ascension's senior care subsidiary.

4. "We are so pleased to welcome the associates, providers and volunteers of Presence Health to Ascension," said Anthony R. Tersigni, EdD, president and CEO of Ascension. "By combining our strengths and learning from one another, we will strengthen Catholic healthcare and our ability to provide compassionate, personalized care in Illinois and in every community across the country where we are privileged to serve."